Excavators are widely used in engineering construction, mining operations and various infrastructure construction, and are indispensable key equipment in modern construction sites. However, due to long-term high-load and high-intensity working environments, excavators will inevitably have various faults during use.Know well about excavator problems and solutions will greatly help with the progress of the project.

Mastering common excavator problems and solutions can not only help shorten downtime and improve operating efficiency, but also effectively extend the service life of equipment and reduce maintenance and operating costs.

This article will systematically sort out the specific manifestations, possible causes and countermeasures of the top ten common excavator problems, helping construction contractors, equipment managers and second-hand users to diagnose and deal with problems more efficiently and ensure the continuous and stable operation of equipment.

1. Excavator Engine Won’t Start

This is perhaps the most common and frustrating of all excavator problems, particularly for machines stored in cold climates or not operated regularly. Engine no-start conditions can be electrical, fuel-related, or due to operator oversight.

Extended Causes:

• Faulty glow plugs (for diesel engines)
• Dirty battery terminals or corroded cables
• Moisture in the fuel system causing freezing
• Faulty neutral safety switch

Diagnostic Tips:

• Use a multimeter to test battery voltage under load.
• Listen for clicking when turning the key — this helps identify starter motor issues.
• Check fuel delivery: Does the lift pump activate? Is fuel reaching the injectors?
• If it cranks but doesn’t start, spray starting fluid into the intake to test combustion.

Brand Tips:

• KATZE Und Komatsu often use ECU-controlled start interlocks—use a diagnostic scanner to retrieve fault codes if no response occurs after key turns.

2. Power Loss During Operation

This excavator problem usually manifests as reduced digging force, sluggish travel, or inability to lift full bucket loads. It’s critical to identify whether the power loss is hydraulic or engine-related.

Further Symptoms:

• Engine sounds normal but machine is weak
• Hydraulic cycle times (boom, arm, bucket) are much slower
• Fuel consumption seems higher than usual

In-Depth Fixes:

• Perform a load-sensing pressure test on the hydraulic pump.
• Check fuel pressure and injector spray patterns.
• Monitor engine performance under load—does RPM fluctuate under stress?

Preventive Insight:

• Don’t mix different hydraulic oils—this reduces lubricity and causes foaming.
• Install a fuel water separator with a clear bowl for better visibility of contamination.

3. Hydraulic System Overheating

This dangerous excavator problem not only slows productivity but also damages internal seals and reduces oil lifespan.

Additional Signs:

• Boom or arm slows down after 15–30 minutes of work
• Sight glass on hydraulic tank shows foam or bubbles
• Hoses feel extremely hot to the touch

Deep Solutions:

• Use an infrared thermometer to map heat sources across the hydraulic system.
• Verify the thermostatic valve in the hydraulic cooler is opening properly.
• Clean hydraulic return line screens, which are often overlooked.

Brands to Note:

• Volvo machines are known for sensitive overheat protection—if over 100°C is detected, the system enters reduced power mode.
• SANY excavators often use dual hydraulic pumps; a failed one may cause one circuit to overheat while the other works.

4. Strange Noises During Operation

Ignoring strange sounds is risky. This excavator problem may be the first and only sign of a major mechanical failure about to happen.

Additional Noise Sources:

• “Squealing” can mean loose belts or dry swing bearings
• “Clunking” often occurs when slew ring bolts loosen
• “Rattling” near the engine could be due to loose exhaust heat shields

How to Investigate:

• Operate the boom and swing while stationary to localize the noise.
• Check for play in bucket and boom linkage by shaking the arm manually.
• Use a mechanic’s stethoscope to pinpoint hydraulic valve ticking or pump cavitation.

5. Track Malfunction

This excavator problem is common in older or heavily used machines. Uneven tracking can wear out undercarriage components rapidly.

Deeper Causes:

• One track moves while the other stalls
• Loose sprockets due to worn hub splines
• Broken travel speed solenoid
• Low planetary gear oil in final drive

Diagnostic Strategy:

• Swap travel motor solenoids from left to right to isolate the problem
• Open the final drive inspection cover—look for milky or low-level gear oil
• Test travel pressure using hydraulic gauges

Tips by Brand:

• Hitachi Und Doosan use electronic sensors for travel logic—these can fail in muddy environments.
• Komatsu travel motors often have replaceable speed sensors and filters that need routine cleaning.

6. Swing System Not Working Properly

An excavator that doesn’t swing or does so sluggishly becomes almost useless in trenching or loading applications.It is one of the most series excavator problems.

Extended Symptoms:

• Swing motor gets hot very quickly
• Machine rotates in one direction only
• Intermittent swing lock

In-Depth Diagnosis:

• Inspect swing brake pressure—stuck brakes can restrict movement
• Check joystick input using diagnostic software
• Remove swing motor and test with bench pressure to confirm bypassing

Preventive Practice:

• Swing bearing must be greased every 100 hours. Use correct lithium-complex grease and rotate while greasing to distribute evenly.

7. Hydraulic Leaks

This is the most visible of all excavator problems, but severity is often underestimated.

Extended Leak Locations:

• Main control valve block
• Swing motor housing
• Joystick control valve
• Auxiliary lines for attachments

Leak Testing:

• Clean the suspected area and wrap in white paper towel to detect fresh oil
• Use UV dye mixed with oil and a blacklight for precise detection
• Temporarily increase hydraulic pressure at idle to force a slow leak to appear

Best Practice:

• Never overtighten hydraulic fittings. Use a torque wrench and manufacturer specs.
• Use Teflon tape or hydraulic thread sealant only where specified—wrong usage can block orifices.

8. Control Panel Not Responding

Modern excavators rely heavily on electronics, and this excavator problem can disable the entire machine if ignored.

Extended Symptoms:

• Joystick doesn’t control boom
• Warning lights flash without pattern
• Control screen freezes or resets

Advanced Fixes:

• Reset the ECU by disconnecting battery for 15 minutes
• Update firmware using OEM diagnostic tools
• Check CAN-bus network for broken termination resistors
• Replace broken fuses with identical amperage only

Insider Tip:

• Always check grounding wires. Poor grounds account for over 40% of unexplained electrical issues.It can greatly reduce the excavator problems.

9. Exhaust Smoke Diagnosis

Different smoke colors point to different excavator problems, from injector failure to oil burning.

Extended Diagnostic Table:

Smoke Color	Cause	Effect	Action
White	Coolant in combustion	Sweet smell, overheating	Test for coolant in oil, pressure test rad
Black	Excess fuel or poor air intake	Poor mileage, soot on turbo	Clean air intake, test injectors
Blue	Oil entering combustion	Oil consumption rises	Inspect turbo seals, valve guides

Tip: Turbochargers often produce blue smoke on startup—if it persists after 3 minutes, investigate further.The smoke color will help us to find the excavator problems easily.

10. Unstable Idling

Unstable or surging idle is one of the more subtle excavator problems, but it affects fuel efficiency and control smoothness.

More Causes:

• Faulty mass airflow sensor (for electronic fuel systems)
• Weak governor spring (in mechanical engines)
• Contaminated diesel fuel

Fix Strategy:

• Run injector cleaner through a full tank and observe idle RPM
• Perform an idle calibration with diagnostic software
• Replace fuel filter and drain water separator bowl

Final Advice:

• Always use clean, filtered fuel. Install pre-filter systems if operating in rural regions.

Preventing Excavator Problems

Beyond solving existing issues, a strong preventive maintenance schedule can drastically reduce the frequency of excavator problems.

Preventive Task	Frequency	Tools Needed
Full fluid inspection	Daily	Dipsticks, sight glasses
Hydraulic pressure test	Monthly	Pressure gauge kit
Undercarriage wear measurement	Biweekly	Tape measure, caliper
ECU diagnostic scan	Quarterly	CAT ET, Komatsu Diagmaster, etc.
Track tension check	Weekly	Track tensioning tool

Zusammenfassung

If you’re working with used excavators from brands like CAT, Komatsu, SANY, or Hitachi, staying informed about these excavator problems can save thousands in repairs and lost time. Proper diagnosis, timely maintenance, and using OEM or high-quality aftermarket parts are the best strategies to keep your machines running reliably.